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<h2 id="ant">Ant</h2>
<h3>Description</h3>

<p>Runs Apache Ant on a supplied buildfile. This can be used to build subprojects.  <strong>This
task must not be used outside of a <code>target</code> if it invokes the same build file it is part
of.</strong></p>

<p>When the <var>antfile</var> attribute is omitted, the file <samp>build.xml</samp> in the supplied
directory (<var>dir</var> attribute) is used.</p>
<p>If no target attribute is supplied, the default target of the new project is used.</p>
<p>By default, all of the properties of the current project will be available in the new project.
Alternatively, you can set the <var>inheritAll</var> attribute to <q>false</q> and only
&quot;user&quot; properties (i.e., those passed on the command-line) will be passed to the new
project.  In either case, the set of properties passed to the new project will override the
properties that are set in the new project (See also the <a href="property.html">property</a>
task).</p>

<p>You can also set properties in the new project from the old project by using
nested <code>property</code> tags. These properties are always passed to the new project and any
project created in that project regardless of the setting of <var>inheritAll</var>.  This allows you
to parameterize your subprojects.</p>

<p>When more than one nested <code>&lt;property&gt;</code> element would set a property of the same
name, the one declared last will win.  This is for backwards compatibility reasons even though it is
different from the way <code>&lt;property&gt;</code> tasks in build files behave.</p>

<p>Properties defined on the command line cannot be overridden by
nested <code>&lt;property&gt;</code> elements.  <em>Since Ant 1.8.0</em>, the same is true for
nested structures of <code>&lt;ant&gt;</code> tasks: if a build file <var>A</var>
invokes <var>B</var> via an <code>&lt;ant&gt;</code> task setting a property with a
nested <code>&lt;property&gt;</code> element and <var>B</var> contains an <code>&lt;ant&gt;</code>
tasks invoking <var>C</var>, <var>C</var> will see the value set in <var>A</var>, even
if <var>B</var> used a nested <code>&lt;property&gt;</code> element as well.</p>

<p>References to data types can also be passed to the new project, but by default they are not.  If
you set the <var>inheritrefs</var> attribute to <q>true</q>, all references will be copied, but they
will not override references defined in the new project.</p>

<p>Nested <a href="#reference"><code>&lt;reference&gt;</code></a> elements can also be used to copy
references from the calling project to the new project, optionally under a different <var>id</var>.
References taken from nested elements will override existing references that have been defined
outside of targets in the new project&mdash;but not those defined inside of targets.</p>

<h3>Parameters</h3>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>antfile</td>
    <td>the buildfile to use. This file is expected to be a filename relative to the <var>dir</var>
      attribute given.</td>
    <td>No; defaults to <q>build.xml</q></td>
  </tr>
  <tr>
    <td>dir</td>
    <td>the directory to use as a <var>basedir</var> for the new Ant project
      (unless <var>useNativeBasedir</var> is set to <q>true</q>).  This will override
      the <var>basedir</var> setting of the called project.<br/>  Also serves as the directory to
      resolve the <var>antfile</var> and <var>output</var> attribute's values (if any).
    </td>
    <td>No; defaults to the current project's <var>basedir</var>, unless <var>inheritall</var> has
      been set to <q>false</q>, in which case it doesn't have a default value</td>
  </tr>
  <tr>
    <td>target</td>
    <td>the target of the new Ant project that should be executed.</td>
    <td>No; defaults to the new project's default target</td>
  </tr>
  <tr>
    <td>output</td>
    <td>Filename to write the Ant output to.  This is relative to the value of the <var>dir</var>
      attribute if it has been set or to the <var>basedir</var> of the current project otherwise.
    </td>
    <td>No</td>
  </tr>
  <tr>
    <td>inheritAll</td>
    <td>If <q>true</q>, pass all properties to the new Ant project.</td>
    <td>No; defaults to <q>true</q></td>
  </tr>
  <tr>
    <td>inheritRefs</td>
    <td>If <q>true</q>, pass all references to the new Ant project.</td>
    <td>No; defaults to <q>false</q></td>
  </tr>
  <tr>
    <td>useNativeBasedir</td>
    <td>If set to <q>true</q>, the child build will use the same <var>basedir</var> as it would have
      used when run from the command line (i.e. the <var>basedir</var> one would expect when looking
      at the child build's buildfile).  <em>Since Ant 1.8.0</em></td>
    <td>No; defaults to <q>false</q></td>
  </tr>
</table>

<h3>Parameters specified as nested elements</h3>

<h4>property</h4>
<p>See the description of the <a href="property.html">property</a> task.<br/>  These properties
become equivalent to properties you define on the command line. These are special properties and
they will always get passed down, even through additional <code>&lt;*ant*&gt;</code> tasks
with <var>inheritAll</var> set to <q>false</q> (see above).<br/>  Note that the <var>refid</var>
attribute points to a reference in the calling project, not in the new one.</p>

<h4 id="reference">reference</h4>
<p>Used to choose references that shall be copied into the new project, optionally changing
their <var>id</var>.</p>

<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>refid</td>
    <td>The <var>id</var> of the reference in the calling project.</td>
    <td>Yes</td>
  </tr>
  <tr>
    <td>torefid</td>
    <td>The <var>id</var> of the reference in the new project.</td>
    <td>No; defaults to the value of <var>refid</var></td>
  </tr>
</table>

<h4>propertyset</h4>

<p><em>Since Ant 1.6</em>.</p>

<p>You can specify a set of properties to be copied into the new project
with <a href="../Types/propertyset.html">propertyset</a>s.</p>

<h4>target</h4>
<p><em>Since Ant 1.6.3</em>.</p>

<p>You can specify multiple targets using nested <code>&lt;target&gt;</code> elements instead of
using the <var>target</var> attribute.  These will be executed as if Ant had been invoked with a
single target whose dependencies are the targets so specified, in the order specified.</p>
<table class="attr">
  <tr>
    <th scope="col">Attribute</th>
    <th scope="col">Description</th>
    <th scope="col">Required</th>
  </tr>
  <tr>
    <td>name</td>
    <td>The name of the called target.</td>
    <td>Yes</td>
  </tr>
</table>

<h3>Basedir of the new project</h3>

<p>If you set <var>useNativeBasedir</var> to true, the <var>basedir</var> of the new project will be
whatever the <var>basedir</var> attribute of the <code>&lt;project&gt;</code> element of the new
project says (or the new project's directory if the there is no <var>basedir</var>
attribute)&mdash;no matter what any other attribute of this task says and no matter how deeply
nested into levels of <code>&lt;ant&gt;</code> invocations this task lives.</p>

<p>If you haven't set <var>useNativeBasedir</var> or set it to <q>false</q>, the following rules
apply:</p>

<p>The <var>basedir</var> value of the new project is affected by the two attributes, <var>dir</var>
and <var>inheritall</var>, as well as the <code>&lt;ant&gt;</code> task's history.  The current
behaviour is known to be confusing but cannot be changed without breaking backwards compatibility in
subtle ways.</p>

<p>If the <code>&lt;ant&gt;</code> task is in a "top level" build file, i.e. the project containing
the <code>&lt;ant&gt;</code> task has not itself been invoked as part of a
different <code>&lt;ant&gt;</code> (or <code>&lt;antcall&gt;</code>) task "higher up", the following
table shows the details:</p>

<table>
  <tr>
    <th scope="col"><var>dir</var> attribute</th>
    <th scope="col"><var>inheritAll</var> attribute</th>
    <th scope="col">new project's <var>basedir</var></th>
  </tr>
  <tr>
    <td>value provided</td>
    <td><q>true</q></td>
    <td>value of <var>dir</var> attribute</td>
  </tr>
  <tr>
    <td>value provided</td>
    <td><q>false</q></td>
    <td>value of <var>dir</var> attribute</td>
  </tr>
  <tr>
    <td>omitted</td>
    <td><q>true</q></td>
    <td><var>basedir</var> of calling project (the one whose build
      file contains the <code>&lt;ant&gt;</code> task).</td>
  </tr>
  <tr>
    <td>omitted</td>
    <td><q>false</q></td>
    <td><var>basedir</var> attribute of the <code>&lt;project&gt;</code> element
      of the new project</td>
  </tr>
</table>

<p>If on the other hand the <code>&lt;ant&gt;</code> task is already nested into another invocation,
the parent invocation's settings affect the outcome of the <var>basedir</var> value.  The current
task's <var>dir</var> attribute will always win, but if the <var>dir</var> attribute has been
omitted an even more complex situation arises:</p>

<table>
  <tr>
    <th scope="col">parent <var>dir</var> attribute</th>
    <th scope="col">parent <var>inheritAll</var> attribute</th>
    <th scope="col">current <var>inheritAll</var> attribute</th>
    <th scope="col">new project's <var>basedir</var></th>
  </tr>
  <tr>
    <td>value provided</td>
    <td>any</td>
    <td>any</td>
    <td>value of parent's <var>dir</var> attribute</td>
  </tr>
  <tr>
    <td>omitted</td>
    <td><q>true</q></td>
    <td><q>true</q></td>
    <td><var>basedir</var> of parent project (the one whose build file called the build file that
      contains the current <code>&lt;ant&gt;</code> task).</td>
  </tr>
  <tr>
    <td>omitted</td>
    <td><q>true</q></td>
    <td><q>false</q></td>
    <td><var>basedir</var> of parent project (the one whose build file called the build file that
      contains the current <code>&lt;ant&gt;</code> task).</td>
  </tr>
  <tr>
    <td>omitted</td>
    <td><q>false</q></td>
    <td><q>true</q></td>
    <td><var>basedir</var> of calling project (the one whose build file contains the
      current <code>&lt;ant&gt;</code> task).</td>
  </tr>
  <tr>
    <td>omitted</td>
    <td><q>false</q></td>
    <td><q>false</q></td>
    <td><var>basedir</var> attribute of the <code>&lt;project&gt;</code> element of the new
      project</td>
  </tr>
</table>

<p>If you add even deeper levels of nesting, things get even more complicated and you need to apply
the above table recursively.</p>

<p>If the <var>basedir</var> of the outermost build has been specified as a property on the command
line (i.e. <kbd>-Dbasedir=some-value</kbd> or a <kbd>-propertyfile</kbd> argument) the value
provided will get an even higher priority.  For any <code>&lt;ant&gt;</code> task that doesn't
specify a <var>dir</var> attribute, the new project's <var>basedir</var> will be the value specified
on the command line&mdash;no matter how deeply nested into layers of build files the task may
be.</p>

<p>The same happens if the <var>basedir</var> is specified as a nested <code>&lt;property&gt;</code>
of an <code>&lt;ant&gt;</code> task.  The <var>basedir</var> of build files started at deeper levels
will be set to the specified value of the property element unless the corresponding Ant tasks set
the <var>dir</var> attribute explicitly.</p>

<h3>Examples</h3>
<p>These are different ways of using the task:</p>
<pre>
&lt;ant antfile=&quot;subproject/subbuild.xml&quot; target=&quot;compile&quot;/&gt;

&lt;ant dir=&quot;subproject&quot;/&gt;

&lt;ant antfile=&quot;subproject/property_based_subbuild.xml&quot;&gt;
  &lt;property name=&quot;param1&quot; value=&quot;version 1.x&quot;/&gt;
  &lt;property file=&quot;config/subproject/default.properties&quot;/&gt;
&lt;/ant&gt;

&lt;ant inheritAll=&quot;false&quot; antfile=&quot;subproject/subbuild.xml&quot;&gt;
  &lt;property name=&quot;output.type&quot; value=&quot;html&quot;/&gt;
&lt;/ant&gt;</pre>

<p>These lines invoke the same build file:</p>
<pre>
&lt;ant antfile=&quot;sub1/sub2/build.xml&quot;/&gt;
&lt;ant antfile=&quot;sub2/build.xml&quot; dir=&quot;sub1&quot;/&gt;
&lt;ant antfile=&quot;build.xml&quot; dir=&quot;sub1/sub2&quot;/&gt;</pre>

<p>The build file of the calling project defines some <code>&lt;path&gt;</code> elements like
this:</p>

<pre>
&lt;path id="path1"&gt;
    ...
&lt;/path&gt;
&lt;path id="path2"&gt;
    ...
&lt;/path&gt;</pre>

<p>and the called build file (<samp>subbuild.xml</samp>) also defines a <code>&lt;path&gt;</code>
with the <var>id</var> <samp>path1</samp>, but <samp>path2</samp> is not defined; then</p>

<pre>&lt;ant antfile=&quot;subbuild.xml&quot; inheritrefs=&quot;true&quot;/&gt;</pre>

<p>will not override <samp>subbuild</samp>'s definition of <samp>path1</samp>, but make the parent's
definition of <samp>path2</samp> available in the <samp>subbuild</samp>, whereas</p>

<pre>&lt;ant antfile=&quot;subbuild.xml&quot;/&gt;</pre>

<p>as well as</p>

<pre>&lt;ant antfile=&quot;subbuild.xml&quot; inheritrefs=&quot;false&quot;/&gt;</pre>

<p>will neither override <samp>path1</samp> nor copy <samp>path2</samp>, while</p>

<pre>
&lt;ant antfile=&quot;subbuild.xml&quot; inheritrefs=&quot;false&quot;&gt;
  &lt;reference refid=&quot;path1&quot;/&gt;
&lt;/ant&gt;</pre>

<p>will override <samp>subbuild</samp>'s definition of <samp>path1</samp>, and</p>

<pre>
&lt;ant antfile=&quot;subbuild.xml&quot; inheritrefs=&quot;false&quot;&gt;
  &lt;reference refid=&quot;path1&quot; torefid=&quot;path2&quot;/&gt;
&lt;/ant&gt;</pre>

<p>will copy the parent's definition of <samp>path1</samp> into the new project using
the <var>id</var> <samp>path2</samp>.</p>

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